The present information relates to an image display system which is applicable to an electronic filing system for reading out image information stored in a memory device and for outputting the image information to a display device, and in particular to an image display system for successively displaying a plurality of pieces of image information read out from, an image memory device having unit image information stored therein on a display; device such as a CRT display and for displaying a particular one of the image information piece with a different display state.
When an objective image information unit or piece of the unit is to be retrieved out of stored image information units in an electronic filing system storing a large amount of image information, it is typical that the objective image information is automatically retrieved by using index information such as a predetermined document name, a classification name or a keyword. Frequently, selection of a desired image information piece or unit having several image information pieces is attempted. In some cases, however, the desired image information unit or piece of the unit is not necessarily extracted by the automatic retrieval on the basis of only the index information inputted by the operator, and a plurality of candidate unit or piece image data are obtained with respect to a certain index information piece that has been inputted.
In some cases, the operator does not memorize the desired image information correctly and hence the operator cannot remember the index information. In these cases, the objective image information is searched for in accordance with only a general idea of the appropriate index information.
In these cases, the operator must select the desired image information piece while observing a plurality of candidate image information pieces extracted by automatic retrieval and displayed on the display apparatus.
An image information retrieval device is described in a patent application in Japan filed by Canon Corporation on Oct. 18, 1984 and laid open as JP-A-61-97784 on May 16, 1986. This device facilitates a visual check by the operator of a plurality of retrieved candidate data on the display at predetermined time intervals to realize a function similar to turning the pages of a book at high speed, for example. When the objective image is found, the operator inputs a stop command via a keyboard, for example, to stop the switching of the displays of, the image.
The display of image information in an electronic filing system will now be described by referring to FIGS. 1A and 1B. It is now assumed that the operator wants to look at a specific page of a desired document. The operator inputs index information relating to the document such as a keyword into the system via an input device of the system. The system retrieves a document containing that keyword in a document storage file device to select pertinent documents. In this case, the number of selected documents is not limited to one. Instead plurality of documents (constituting a document group) are often selected. The display capability of the screen is exceeded when all of the selected documents on the display device are displayed at a time. Accordingly, parts of respective documents are reduced in size and displayed or a list containing titles of documents and summaries of their contents is displayed on the screen so that the operator may watch the screen and select a desired document via the input device. When a plurality of documents have been selected, the operator observes pages of respective documents successively display on the display screen by using the page turning function of the system and selects a page of a desired document.
FIG. 1A shows a state in which a group of documents A, B and C have been selected as candidates by the automatic retrieval operation of the system. The document A contains three pages of P. 1 to P. 3 and the document B contains two pages of P. 1 and P. 2 whereas the document C contains three pages of P. 1 to P. 3. On the display screen, all of the three documents may be displayed as shown in FIG. 1A (where respective pages are overlapped and displayed), or alternatively a list of the titles of the documents may be displayed. If the operator selects the page turning feature via the input device, the screen changes in the direction of arrows illustrated in FIG. 1B each predetermined time interval. First of all, P. 1 (the first page) of the document A is displayed on the screen for approximately one second. Subsequently, P. 2 (the second page) of the same document A is displayed for approximately one second. A page of each document is thus displayed every one second, and the display of the documents ends with P. 3 (the third page) of the document C. If a desired document page is found during that time, the operator stops the turning of the pages.
In the above described electronic filing system, image information data are stored in an image storage device (such as a magnetic recording device or an optical disk device) while taking a series of "documents" each comprising one or more pages as one unit., and the retrieval processing is also performed while retrieving the documents as one unit.
When a plurality of document images extracted by the retrieval are consecutively displayed on the screen at predetermined time intervals, they are displayed by document page rather than by the document as a unit. The duration of display of any document page is identical, and the switching time between pages is also uniform.
Therefore, it is difficult for the operator to determine the boundary between different documents in a moment. Oversight or misjudgment of the image of the desired page is often caused by oversight of the boundary between different documents.
Further, in many documents (such as patent specifications), important bibliographic matters of the document are described on the first page of the document. It is thus one of the important objects to make the first page of each document easily recognizable to an operator.